FIG. 2 is a flowchart showing the steps included in a conventional method of manufacturing heat radiating fins.
In a first step (11), a metal material is prepared. The metal material may be a sheet metal material 2 as shown in FIG. 1A to be used as a raw material for manufacturing a heat radiating fin. The sheet metal material 2 may be aluminum or copper or other heat conducting sheet materials.
In a second step (12), the sheet metal material 2 is positioned on a punching mold for punching.
In a third step (13), the sheet metal material 2 is primarily shaped by punching to form two opposite edges 21 with two hooking ends 211 each, as shown in FIG. 1B.
In a fourth step (14), the two opposite edges 21 are bent, so that an angle about 90 degrees is contained between the bent edges 21 and a main body of the sheet metal material 2 to complete a heat radiating fin, as shown in FIG. 1C.
In a fifth step (15), use a tool to stack a plurality of the heat radiating fins obtained in the fourth step (14), so that the hooking ends 211 on the two bent edges 21 of an upper heat radiating fin are rested on the hooking ends 211 on the two bent edges 21 of a lower heat radiating fin, as shown in FIG. 1D.
In a sixth step (16), the hooking ends 211 on each heat radiating fin are separately bent inward to hook on an adjacent heat radiating fin, so that the two heat radiating fins are connected to each other, as shown in FIG. 1E.
In the conventional method, the heat radiating fins are manufactured by way of punching or stamping, so that the sheet metal material 2 is punched or compressed to obtain desired shape and mechanical properties. In either way, the sheet metal material 2 must be cut and bent at two opposite edges, so as to form the hooking ends and hook the bent hooking ends on one heat radiating fin to another heat radiating fin, and thereby connect two stacked heat radiating fins.
Most currently available heat sinks are formed by stacking aluminum or copper heat radiating fins, and the stacked heat radiating fins are hooked and connected together by the hooking ends formed on two bent edges of the sheet metal material 2 using punching or stamping molds. The size and shape of the hooking ends, as well as the manner of hooking and connecting two adjacent heat radiating fins via the hooking ends must vary with different types of products. Errors in the size of the bent edges and hooking ends easily occur in the manufacturing process. The hooking ends are separately formed at two bent edges of the sheet metal material and therefore have relatively low structural strength and tend to deform when they are adjusted, pulled, or pushed under an external force. Once the hooking ends are deformed, it is difficult to repair or remake them. Even if the deformed hooking ends are adjusted or repaired, they might not be exactly restored to the original shape or size.
The heat radiating fins manufactured in the conventional method have relatively complicated structure, and therefore require experienced and skilled persons and longer time to design and perform the fabrication of the heat radiating fins. Even so, the bad yield is still high.
The molds used in the conventional method to manufacture the heat radiating fins usually include small parts which are subject to damage easily, and must also be designed and produced at high precision. Besides, slide blocks are often needed in the molds for the conventional method of manufacturing heat radiating fins to further complicate the mold structure and increase the time for developing and repairing the molds, resulting in additional costs. In summary, the conventional method of manufacturing heat radiating fins has the following disadvantages: (1) the hooking ends on the heat radiating fins are easily deformable; (2) the molds therefor are complicate and expensive; (3) the overall manufacturing cost is high; (4) the heat radiating fins have complicated structure and require more time and labor to manufacture; and (5) the molds includes small parts that damage easily.
It is therefore tried by the inventor to develop an improved method of manufacturing heat radiating fin to overcome the drawbacks in the conventional method.